A number of medical applications require the injection of significant amounts of material. For example, one such application is the injection of dermal fillers to correct facial wrinkles or folds. In such a procedure, a possibly significant quantity of dermal filler material is injected under the skin using a syringe. In addition, the material injected may have a higher viscosity than the substances typically injected by syringe. For example, some dermal fillers may include gels, such as a gel made of hyaluronic acid. Traditional syringes and the plunger rods used with such syringes present a number of problems when used for such applications. For instance, in order to accommodate significant volumes of material, such syringes must typically have either a large length or cross-sectional area. Syringes with larger cross-sectional areas are often not practical, however, because the extrusion force required to operate a syringe increases with the cross-sectional area, this may be particularly problematic when injecting viscous fluids. Increasing the length of a traditional syringe, however, may significantly increase the overall length of the device, as a longer plunger may also need to be used, which may reduce the user's comfort and control during use. Accordingly, example embodiments provide improved plunger rods which may address a number of the shortcomings of traditional plunger rods.